6 <div class="well notabene">
7 Ardour's VBAP panner is currently in development, and its semantics may
8 change in the near future, possibly affecting your mixes. Please do not
9 rely on it for important production work while the dust settles.
12 <strong>VBAP</strong> is short for <em>Vector-base Amplitude Panning</em>,
14 straightforward method to pan a source around on an arbitrary number
15 of speakers on a horizontal polygon or a 3D surface, even if the speaker
16 layout is highly irregular.
19 <h2>Basic concepts</h2>
21 VBAP was developed by Ville Pulkki at Aalto University, Helsinki, in 2001.
22 It works by distributing the signal to the speakers nearest to the desired
23 direction with appropriate weightings, aiming to create a maximally sharp
24 phantom source by using as few speakers as possible:
27 <li>one speaker, if the desired direction coincides with a speaker
29 <li>two speakers, if the desired direction is on the line between two
31 <li>and three speakers in the general 3D case.</li>
34 Thus, if you move the panner onto a speaker, you can be sure that only
35 this speaker will get any signal. This is handy when you need precise
37 The drawback of VBAP is that a moving source will constantly change its
38 apparent sharpness, as it transitions between the three states mentioned
42 A horizontal VBAP panner has one parameter, the <strong>azimuth
43 angle</strong>. A 3D panner offers an additional <strong>elevation
44 angle</strong> control.
47 More elaborate implementations of VBAP also include a
48 <strong>spread</strong> parameter, which will distribute the signal over a
49 greater number of speakers in order to maintain constant (but no longer
50 maximal) sharpness, regardless of position. Ardour's VBAP panner does not
51 currently include this feature.
54 <h2>Speaker layout</h2>
56 Each VBAP panner is specific to its <strong>speaker layout</strong>
57 — the panner has
58 to "know" about the precise location of all the speakers. A complete VBAP
59 implementation must therefore include the possibility to define this
62 <img src="/images/VBAP-panner-5.png" class="small right" alt="The VBAP
63 panner with 5 outputs"/>
65 Ardour currently uses a simplified approach: if a track or bus has more
66 than two output channels (which implies stereo), it assumes that you
67 have N speakers distributed in a regular N-gon. That means that for
68 irregular layouts such as 5.1 or 7.1, the direction you dial in will
69 differ a bit from the actual auditory result, but you can still achieve
70 any desired spatialisation.
72 <h3>Experimental 3D VBAP</h3>
73 <img src="/images/VBAP-panner-10.png" class="small right" alt="The VBAP
74 panner with 10 outputs, in experimental 3D mode"/>
76 For tracks with 10 outputs, Ardour will currently assume a 3-dimensional
77 speaker layout corresponding to Auro-3D 10.1, which is a horizontal 5.1
78 system, four elevated speakers above L, R, Ls, and Rs, and an additional
79 "voice-of-god" speaker at the zenith.
83 <img src="/images/VBAP-panner-4in5.png" class="small right" alt="The VBAP
84 panner in 4 in, 5 out mode"/>
86 For tracks and busses with more than one input, Ardour will (for now) assume that
87 you wish to distribute the inputs symmetrically along the latitude around
88 the panner direction. The width parameter controls the opening angle of
89 the distribution sector.